Despite the availability of a variety of highly effective antibiotics, the search for new antibiotics is a continuing one. The primary reason for the continuing search is the reoccurring development of microorganisms which are resistant to existing antibiotic therapy. Thus there is a continuing need for new antibiotics which are either intrinsically more active than existing drug entities and thus can be administered in lower dosages to minimize the side effects of these powerful drugs, or are effective against resistant strains.
A number of aminoglycoside antibiotics are known, such as the gentamicin and kanamycin family of antibiotics. More recently, a new family of aminoglycosides, the fortimicins have been identified. See, for example, U.S. Pat. Nos. 3,976,768 and 3,931,400.
Although the fortimicin family is a relatively new group of antibiotics, clinical experience has shown that aminoglycoside antibiotics are susceptible to the resistant strain problem. In many cases, the resistance is R-factor mediated and is attributed to the ability of the bacteria to enzymatically modify the amino or hydroxy groups of the aminoglycoside antibiotics.
Thus, there is a continuing need for new antibiotic entities in this valuable antibiotic family. The present invention provides one such entity.